Browning Mainspring pressure - How much is good enough

[twoguns]

I have two new springs coming from MGW for my Browning 1886. I cut the original one a wee bit too short during my action smoothing exercise and it won't light off my primers. I think it is a combination of the inertia firing pin structure and mainspring pressure. Does anyone have the magic formula to get the mainspring pressure balanced so that the action cycles smoothly but light up the primers?

[J Miller]

twoguns,

Here is my method of doing that. I stick in the weakest spring and then go shoot ammo loaded with CCI primers. If it pops them all the first time every time, I stop there. If I get even so much as one that doesn't fire I go up to the next heavier spring and shoot more CCI primered ammo.
It's a royal pain in the patootie but since each gun is different I really don't know any "formula".
I can tell you this. My Rossi Puma .45 Colt I had worked great with the Wolff 19# Ruger Blackhawk main spring. Just enough ooomph to positively fire CCI primers but not so much to heavy up the action.

Joe

[Shasta]

I had a similar problem with my Marlin 39A. After trimming the coil mainspring, I experienced a few failures to fire. I solved the problem by shimming the mainspring with small, thin stainless steel flat washers with the holes filed out to fit over the mainspring guide rod. After installing two washers the misfires were gone and the action remained light and smooth.

SHASTA

[B-92 Steven]

Twoguns, In my message/entry "Model 92 mainspring replacement" is similar to your question. I feel the mainspring in my Browning is too stout for smooth cycling. What I want to do is find a replacement mainspring and found something I hope would work at Brownells. I would perfer not to cut the original mainspring so I can put it back if I ever needed to. I read Joe'e reply where he used Ruger springs. Anyone else have springs that would work?